code: def test_UndecoratedTest(self):
      with self.assertRaises(ValueError):
  
          @metrics.MonitorBoolGauge("unknown")
          def func(x):
              return x + 1
  
          func(1)
  
file_path: model-optimization/tensorflow_model_optimization/python/core/keras/metrics_test.py
imports: import mock
  import tensorflow
  from tensorflow.python.eager import monitoring
  from tensorflow_model_optimization.python.core.keras import metrics
label_desc: Use image node_id 4 for calling the MetricsTest obj's underlying member method code with example usage: obj.test_UndecoratedTest() and returns: unknown